1. Field of the Invention
This invention relates to an electronic image recording apparatus and data memorizing method therefor. More particularly, this invention relates to an electronic image recording apparatus, such as a digital still camera, and a data memorizing method, adapted to write image data different in size into small areas, in number appropriate for a data size, formed in a flash memory, and erase desired image data from the flash memory.
2. Description of the Prior Art
In the conventional digital still camera of this kind, image data photographed and compressed are recorded in a flash memory in the order from a first As address thereof, as shown in image data area in FIG. 8. Here, the compressed image data has a size dependent upon its subject so that the image data {circle around (0)}-{circle around (5)} written in the flash memory are different in size therebetween. If the image data {circle around (1)}, {circle around (2)} and {circle around (4)} are then erased, the flash memory will have vacant areas as shown in FIG. 8(B). In this state, if a double exposure is made, image data {circle around (6)} and {circle around (7)} are respectively stored at unoccupied areas as shown in image data area B in FIG. 8.
However, the image data size is dependent upon a subject thereof, as stated above. Accordingly, if new image data is written on a vacant area given by erasing the recorded image data, small vacant areas will be left there. That is, exposure and erasure are repeatedly made, strip-formed vacant areas are sporadically left, giving rise to a problem of lowering service efficiency of the flash memory.
In order to solve such a problem, another conventional digital still camera is structured by an FAT (File Allocation Table) and an image data area divided into a plurality of small areas, so that the allocating information to the small areas is stored into the FAT. With this structure, when the image data {circle around (6)} and {circle around (7)} are written in a state of image data area B in FIG. 8, the image data {circle around (7)} is recorded into small areas that are distant from one another, thereby preventing against the formation of vacant areas within the image data area.
However, the digital still camera with this structure requires renewal to the FAT each time exposure or erasure is made, raising a problem of reducing the life of the flash memory. That is, the erasure from a flash memory is possible only by a unit called page having several kilo bytes to several tens of kilo bytes. Also, there is a limitation to a frequency capable of rewriting to a flash memory. If erasure and writing are repeated on a same address, the memory characteristics suffer from deterioration and ultimately becomes impossible to be written.
Therefore, it is a primary object of this invention to provide a novel electronic image recording apparatus.
It is another object of this invention to provide an electronic image recording apparatus which is capable of enhancing service efficiency for a flash memory and extending the life of the flash memory.
An electronic image recording apparatus according to this invention, comprising: an image inputting means for inputting image data for one image, the image data being configured by a plurality of partial image data; a nonvolatile RAM for recording the image data, the RAM including a plurality of memory areas each having a same memory capacity, the memory areas each including an image data storing section for storing partial image data and a link information storing section for storing link information; an image data writing means for writing the plurality of partial image data separately onto the respective image data storing sections of the plurality of memory areas; and a link information writing means for writing the link information linking between the plurality of memory areas.
Specifically, the link information includes address information representative of a related memory area, and further the address information includes a head address of the related memory area.
According to this invention, partial image data for constituting one image are separately stored in the memory areas of the nonvolatile RAM while link information for linking between the plurality of memory areas is written to the memory areas. Accordingly, the nonvolatile RAM is improved in utilizing efficiency, and does not require especial areas formed for storing the link information. Therefore, even where using a flash memory as the nonvolatile RAM, the life of the flash memory can be extended because a certain particular area is not frequently rewritten.
In one aspect of this invention, an electronic image recording apparatus includes a nonvolatile RAM, the nonvolatile RAM including a plurality of memory areas written with partial image data, and the plurality of the memory areas storing link information for linking between the partial image data.
A digital camera according to this invention, includes a flash memory, the flash memory includes a plurality of memory areas written with sporadic partial image data, and the plurality of memory areas memorizing address information for linking between the partial image data.
This invention is a data memorizing method for an electronic image recording apparatus adapted to store image data into a nonvolatile RAM, comprising the steps of: (a) writing first partial image data of first image into a first memory area; (b) searching a vacant memory area when the first memory area is filled up; (c) writing second partial image data of the first image into the vacant memory area as a second memory area; (d) writing a head address of the first memory area to the second memory area; and (e) writing a head address of the second memory area to the first memory area.
This method includes a step of (f) writing a succeeding image number to a succeeding memory area when the writing of all the partial image data for the first image is completed. Therefore, at the step (a), the first partial image data is written into the vacant area, as the first memory area, stored only with an image number.
In a digital camera according to one aspect of this invention, image data different in size are written into small areas, in number appropriate for a data size, formed in a nonvolatile RAM, and desired image data is erased from the nonvolatile RAM. The digital camera is characterized in that image data includes a plurality of partial image data of a same size as the small area, and a first address data writing means being provided to write head address data of a current small area to be written by current partial image data into correlated small area that is correlated to the current small area.
If the partial image data constituting the image data is written into the small area formed, for example, in a flash memory, the head address data of the small area is written into the small area written by the precedent partial image data to the partial image data. That is, linkage is formed between the small areas written by the image data. Therefore, even if the plurality of the small areas written by the image data are distant from one another, the image data can be reproduced or erased by tracing the head address data.
In this aspect, since the head address data of the current small area is written into the correlated small area that is correlated to the current small area, image data can be written by division into small areas existing distant from one another, enhancing the service efficiency of the RAM. Also, the writing of head address data eliminates the necessity of the conventional FAT, extending the life of the RAM.
The above described objects and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.